Rolling-element bearings, in particular ball bearings, are used in various locations on bicycles. These include, among other, the bottom-bracket bearing, the wheel hubs, the steering-tube- or headset-bearing, the rear-derailleur roller bearing, as well as bearing assemblies of the swingarm chainstay. When the bicycle is used in muddy or other dirty areas, with fresh- or salt-water contact, as well as with rainy and windy weather conditions, followed by possibly strong cleaning forces, e.g., with the use of a high-pressure cleaner, these bearings are also subjected to heavy loads. This applies in particular for mountain bikes which tend to be used in harsh conditions.